Autism disorders are characterized by repetitive behaviors and deficits in social communication. About 1 in 68 U.S. children has an autism spectrum disorder, the CDC now reports.

Geographically, the differences among states tested are stark: 1 in 175 children were diagnosed with autism in Alabama, while 1 in 45 New Jersey children received an autism diagnosis.

Nationwide, it's likely that the increase is due to heightened disease awareness, more screening within schools, and a willingness to label the condition, says the CDC. State-by-state numbers can be explained similarly.

"[The difference among states] is not because there's something going on in the drinking water in New Jersey and that kids in Alabama are spared this environmental exposure," says Lisa Shulman, director of infant and toddler services at the Albert Einstein College of Medicine's Children's Evaluation and Rehabilitation Center in New York City.

"It's access to systems and institutions that diagnose and evaluate," Shulman adds. "There's so much variability geographically in terms of finding cases."

The CDC began tracking autism prevalence in the early 2000s and releases new findings every two years. To get the most recent results, CDC researchers looked at the medical records of eight-year-olds who lived in 11 specific areas within the United States.

Though this CDC report is important, it is by no means perfect, experts caution. The fact that it's a retrospective study and looks at only 11 sites within the U.S. means that the results could be skewed.

The increase in autism cases is also not surprising, says Craig Newschaffer, director of the A.J. Drexel Autism Institute in Philadelphia. This year's results, he says, are a continuation of a trend and not a sudden jump. Increased awareness among parents, schools, and organizations has led to more diagnoses, he says.

"Autism [is] more of a household word," says Shulman. "You literally have to be living under a rock to not have heard of autism."

Autism also carries less stigma than it has in the past, says Leslie Markowitz, a pediatric psychologist at the Cleveland Clinic Children's Center for Autism. What with recognition from insurance companies, publicly funded programs for autistic children, and the rise of advocacy organizations like Autism Speaks, people may be more likely to seek the diagnosis, she says.

The number of autism cases is likely to increase further in 2016 when the next CDC report is released. That's because the medical community has changed the diagnostic criteria, including a wider spectrum of disabilities and making it easier for physicians to label their patients with the term.

For those concerned about possible environmental risk factors for autism, experts urge caution. Though the environment may play a role in some of the observed uptick, it is likely a very small one, says Mark Cohen, a developmental pediatrician at the Kaiser Permanente Santa Clara Medical Center.

New diagnostic criteria and better access to care are behind most of the new cases, and parents-to-be should not panic, Cohen says.

"It would not surprise me if the numbers get higher, and it doesn't alarm me," he adds.